Method of connecting underwater installations

ABSTRACT

A ship is provided with a through-hull well extending from the upper deck 3 through the main deck 2 to the ship&#39;&#39;s bottom. A derrick 4 is positioned on the upper deck above the well. To assemble a multi-unit load for lowering to the sea bottom, a sliding platform 10 at the main deck level is moved over the well opening. A sliding crane just below the upper deck then transports a first load unit from a storage area adjacent the well to the platform. The crane is then withdrawn, the load unit is restrained against lateral movement in vertical guides, and is raised up into the derrick. Additional load units are delivered in this manner to the platform and coupled to the unit(s) above it to produce the final load. The platform is then slid back from the well opening and the load is lowered by the derrick to the sea bottom.

United States Patent 1191 Mercier et al.

' June 18, 1974 221 Filed:

[54] METHOD OF CONNECTING UNDERWATER INSTALLATIONS [73] Assignee: SubseaEquipment Associates Limited (SEAL) 211 App]. No.: 299,551

[30] Foreign Application Priority Data Oct. 21, 1971 France 71.37808[52] US. Cl 214/152, 114/05 D, 212/3, 214/2.5, 214/13 [51] Int. Cl E211)3/00 [58] Field of Search ..214/l2,13,14,15 R, 15 E, 214/152, 2.5;114/05 D; 29/428, 464, 468,

FOREIGN PATENTS OR APPLICATIONS 1,124,425 7/1956 France 2l4/2.5

Primary Examiner-Frank E. Werner Attorney, Agent, or Firm-Sughrue,Rothwell, Mion, Zinnv & Macpeak [5 7] ABSTRACT A ship is provided with athrough-hull well extending from the upper deck 3 through the main deck2 to the ships bottom. A derrick 4 is positioned on the upper deck abovethe well. To assemble a multi-unit load for lowering to the sea bottom,a sliding platform 10 at the main deck level is moved over the wellopening. A sliding crane just below the upper deck then transports afirst load unit from 'a storage area adjacent the well to the platform.The crane is then withdrawn, the load unit is restrained against lateralmovement in vertical guides, and is raised up into the derrick.Additional load units are delivered in this manner to the platform andcoupled to the unit(s) above it to produce the final load. The platformis then slid back from the well opening and the load is lowered by thederrick to the sea bottom.

3 Claims, 16 Drawing Figures PATENTEDJun 18 I974 SHEET 3 [IF 8PATENTEDJUNIBISM mar/L412 SHEET 0F 8 PATENTEDJUH 18 m4 SHEEI S (If 8PATENTEUJun 18 m4 SHEET 8 [IF 8 METHOD OF CONNECTING UNDERWATERINSTALLATIONS BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to a method and apparatus connecting up withunderwater installations, such as an oil well, from a vessel or adrilling platform.

2. Description of the Prior Art Various vessels are already known,capable of being employed for connecting up with oil wells, but thesevessels are specially adapted for drilling and not for setting heavyequipment in place. Vessels can also be specially designed for aparticular method of setting the underwater installation in place or ofcontrolling the working of a well, but these vessels are very costly anddo not enable the control of installations at depths exceeding 50meters. As for fixed surface platforms comprising only a derrick and awell, none of them enable, in spite of heavy hoisting equipment, therapid and easy placement of an underwater installation in deep water,this operation necessitating the transport, handling and precise settingin place of heavy and bulky units.

Moreover, the displacement of heavy loads on board ship cannot becarried out without special precautions since the surface vessel issubjected to pitching, rolling or yawing movements caused by groundswells and waves. In spite of the precautions taken, the heavy strainsto which the hoisting equipment would be subjected during variations inacceleration of the loads prevent its use in the event of even smallvariations in the trim and list of the vessel. Furthermore, since heavyhoads cannot be raised and left free to shift laterally because of theobvious dangers incurred, the problem of handling heavy loads of to 100tons, for example, prohibits any work of setting in place or connectingup with underwater installations from being done as soon as significantpitching, rolling or yawing movements of the vessel appear.

SUMMARY OF THE INVENTION According to the present invention there isprovided a method of unloading an underwater apparatus from aninstallation on the water surface, whether subjected or not to theaction of ground swells and waves, and comprising a deck carrying aderrick, a well straight below the latter and opening into a storagearea below the deck, a platform capable of supporting and attaching thesaid loads positionable across the well, and load transport means in thestorage area, the method comprising making a load fast with thetransport means, transporting the load to the platform when the platformspans the well, making the load fast with the platform, disengaging theload from the transport means, which is moved back into the storagearea, positioning lateral guide means in contact with the loadconnecting the load to the hoisting means of the derrick and disengagingit from the platform, drawing the platform back out of the well, andlowering the load down the well while guiding it laterally.

Such a method presents the advantages of being able to be easily appliedto any ship, and in particular to any ship and drilling platform, ofeffecting permanent immobilization of the load being transportedrelative to its support in spite of movements of the surfaceinstallation, of being cheap from the customary means capable of beingemployed, and of enabling the assembly together of bulky loads above theinstallation well, even in the case of relatively reduced dimensions inthe height of the ship.

In fact-it is sufficient when hooking the first load onto the hoistingmeans of the derrick to bring this upwards above the well to be able torepeat the same maneuver as has just been described, and then toassemble the new load resting on the platform with the load carried bythe derrick. It goes without saying that this method enables theassembly of any number of loads before the lowering of the whole unitproduced.

The lateral guidance of the load in the well may be effected bysurrounding it with a movable frame which is attached to the load at thelevel of its center of gravity and which is made to slide on verticalretractable guides.

The advantage of this method is in enabling the easy transport of heavyloads of any shape through the well in spite of the trim and list of theship, the retractable guides enabling the passing of the load and itscarrying means to the junction between the well and the store.

According to the invention there is further provided a system foreffecting the above defined method of this invention which comprises astorage area, a well extending downward from through the storage areaand a deck over the storage area carrying a derrick straight above thewell, and a movable platform capable of adopting at least two positions:one spanning the well to receive these loads, the other displaced fromthe well to permit passage of loads to the well, the platform havingmeans for attaching loads thereto.

Such a system may be easily installed on drilling ships since theseinclude a main deck through which the well passes.

The deck carrying the derrick may include a staging opening at rightangles to the derrick, the latter having guide means in extension of thewell guides.

This arrangement therefore enables the vertical assembly of a number ofloads straight above the well, while, when the staging is in the closedposition, allowing the use of any suitable means for screwing connectingtubes to the load or to the assembly of loads which are to be lowered tothe seabed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a longitudinal section ofthe connecting-up system according to the invention on board a drillingship, the fore and aft portions of which have been removed;

FIG. 2 shows a section along the line IIII in FIG. 1;

FIG. 3 shows a transverse section of the coupling-up system;

FIG. 4 shows the section along the line IV-IV in FIG. 1;

FIG. 5 shows a plan view of the bridge crane and its crab;

FIG. 6 shows an elevation of the bridge crane;

FIG. 7 shows a section of the device for attaching the load to the crabof the bridge crane, along the line VII- VII in FIG. 6;

FIG. 8 shows an elevation of a load-retaining ear and a hook of thehoisting tackle of the bridge crane crab",

FIG. 9 shows a plan view of the platform;

FIGS. and 11 show two diagrammatic views of the platform locking devicein the locked and unlocked positions;

FIG. 12 shows a section along the line XII-XII in FIG. 9',

FIG. 13 shows a detail of the device for attaching the load to theplatform;

FIG. 14 shows a diagrammatic view of the system showing the loadsassembled on the platform;

FIG. 15 shows a diagrammatic view of the system in the course oflowering the loads; and

FIG. 16 shows a diagrammatic plan view of a collar for retaining theloads in the course of their vertical displacement.

Although the following description refers to a system mounted on adrilling ship, it will be understood that this system can be mounted onany suitable installation, such as a drilling platform, for example. Ithas therefore been considered unnecessary to show the whole drillingship. The zone of the ship serving as the storage area can have anysuitable dimensions. In the example shown, this zone is bounded bystaging 2 of the main deck and an upper deck 3 on which is a derrick 4.This zone extends both fore and aft from a well, bounded laterally inits lower portion by bulkheads 5 and by bulkheads 6, FIG. 3, in itsupper portion. In fact the zone might possibly extend only aft or onlyforward. A first horizontal rollway shown diagrammatically at 7 carriesa bridge crane, shown diagrammatically at 8, FIG. 3. A second rollway 9carries a working platform shown diagrammatically at 10.

The lower portion of the well contains vertical guides 11, FIGS. 1, 3and 4, mounted on retractable frames swinging about mountings l2; arms13 controlled by jacks (not shown), but like jacks 19 shown in FIG. 2,ensure locking of the frames when the guides 11 are in the workingposition.

Guides 14, FIGS. 1 to 3, likewise mounted on retractable frames 18rotatable about mountings 15, provide guidance of loads in the upperportion of the well. Arms 16 swinging on mountings 17 ensure locking ofthe guides in the working position.

The arms 16 can be replaced by jacks l9 hinged to ears 20 and shown indotted lines, FIG. 2, in the work ing position and in the parked orretracted position.

Upwardly retractable guides 21 in extension of the guides 14 provideguidance for loads in the interior of the derrick.

The guides 14 are movable vertically and can lift to connect with theguides 21 by means of spigots 23.

The guides 14 can be lowered to connect with the guides 11 by means ofspigots 22. According to one variation. instead of slidable guides 14,guides fixed on their frames can be provided and independent retractableconnections can be provided ensuring continuity of vertical guidanceofloads in the course of their passing from the lower portion of thewell to the upper portion and thence to the interior of the derrick,when the platform 10 and the bridge crane 8 are out of the well. Theslidingguides 14 can be controlled by any device, motor or manual, andare balanced by means of a counterweight. The control device can be ofany suitable kind known in the art and accordingly has been showndiagrammatically at 24.

The derrick can also be equipped with slidable guides 21 capable ofconnecting with the guides 14, the guides 14 or 21 having at their endsspigots or any other means facilitating the joining up.

In order to avoid any swinging to and fro of the loads in the course oftheir passing through the well and the derrick, a retaining collar 25has been provided for, having any sort of device for laterally retainingthe load being transported. By way of example the collar can be providedwith jacks similar to those indicated by 26, the rods 27 of which haveat their ends pads 28, such jacks 26 being provided to prevent impactsof the load against the hull of the ship at the end of the well. Thepads 28 can be of any suitable type.

The retaining collar 25, as shown in FIG. 16, can, as an alternative tojacks, be provided instead with inflatable bolsters 26a preferablyhaving walls of reinforced rubber. These bolsters 260 are distributedaround a circle on a collar 27a fixed to the collar 25 by parts 29. Thebolsters 26a are independently inflatable with water to ensure thecentering of the load being transported. Thus the load and the collar 25are made fast with one another, the latter sliding on the guides ll, 14and 21 by shoes 30.

The passing of the load into the derrick is effected through aretractable staging, FIG. 3, composed of panels 31 and 32.

According to a preferred embodiment of the invention the axis of thewell coincides with the axis of the platform and that of the supportingcables of the derrick tackle.

The bridge crane 8 servicing the storage area and the well is shownpartially in plan in FIG. 5. Four winches 33 mounted on the crab 34enable the loads to be raised by means of hooks 65, FIG. 8, attached tocables wound around the drums of the winches after passing over sheaves66. The points of attachment of the cables to the crab constituting thefixed points of the tackle are adjustable and have elastic suspensiondevices. This arrangement enables the tensions in the cables to beequalized and the height of the hooks to be adjusted to the same level,thus facilitating the hooking on of the load by sling lugs 67.

The transfer movements of the crane in the longitudinal direction areeffected by means of the motor 35, reduction gears 36 at each end of thegantry 37, driving pinions 38 and racks 39. The crane rests on therollways 7 by means of supporting rollers 40, vertical and horizontalretention rollers 41 and 42 ensuring stability of the crane.

The motor 43 provides transfer of the crab across the crane by means ofreducing gears 44, pinions, and racks 49. Supporting rollers 45 andhorizontal and vertical retention rollers 46 and 47 ensure stability ofthe crab.

The drive of the drums of the winches 33 is effected by a motor 50 andreduction gears 51. A solenoid brake 52 controls the drive, andemergency brakes S3 enable rapid stopping of the hoist winches 33.

Two columns 54 arranged under the gantry 55 and integral with the crab34, enable lateral retention of the loads being transported. The loadsare restrained against any lateral movement by at least one of thecolumns. The latter are provided with sheaths 56 attached tocounterweights 57 by means of cables 58 and pulleys 59. Attachment ofthe loads is effected by means of single detachable ears or multipleones as shown in FIG. 7 at 60, 61, 62, these ears being integral with asupport 63 that is attached to one of the ears 64 integral with thesleeves 56. The level of the sleeve is adjusted so that the fixing earin use is practically at the level of the center of gravity of the load.An excellent immobilization of the load is thus obtained. It goeswithout saying that the method of attachment of the support 63 to theears 64 can be of any kind and that the means shown are given only byway of example.

The rolling platform 10, FIGS. 9 and 12, is located in the floor of thestore. The rollway 9 and racks 68 enableits displacement up to the frontof the wall. Transfer motor 69 drives, through reducing gears 70,driving pinions 71 engaging the racks 68. Supporting rollers 72 roll onthe way 9.

Locking devices 73 shown in the locking position in FIG. and theunlocking position in FIG. 11 keep the platform in the requiredposition. A comb 74 is operated for this purpose to come into engagementwith or disengage itself from the rack 68 by a lever 75 articulated to alink 76 and to a spring guide 77 by means of a cranked lever 78.

Attachment points 79 more easily seen in FIG. 13 enable immobilizationof a load 80 being transported by means of claws 81 held by means ofbolts, projections 82a on which bear against stops 79a when a nut 83tightens the claw 81.

The system which has just been described enables the method of theinvention to be illustrated. If the diagrammatic FIGS. 14 and arereferred to, a unit 84 is seen to be already assembled and suspended onthe collar of hoisting tackle 85 of the derrick 4.

Suppose the unit 84 is composed of three loads: 86, 87 and 88. Theseloads are stored originally in zone 89 enclosed in the given examplebetween the upper deck 3 and the main deck 2. The platform 10 havingbeen brought into the well, and the crab of the bridge crane into aposition enabling hooking-on of the load 86, the latter is attached toone ear of the sheath whose height is adjusted so that the ear is at thelevel of the center of gravity of the load. Then the crane is moved upto the well in order to deposit the load on the platform 10 and movedaway again after fixing the load to the platform. If the guide rails 14are not already out they are locked in the working position after theload has been enclosed in the retaining collar 25. Having raised thesliding guides 14 and centered them on the spigots 23 to establishcontinuity with the guides 21, the load is hooked onto the tackle 85 andthe load 86 held by the collar 25 is raised into the derrick. The guides14 are then lowered to enable the bridge crane to pass by again, whichis employed as before to deposit the load 87 on the platform. Afterwithdrawal of the crane the load 86 is lowered onto the load 87 in orderto fix them to one another. Possibly the retaining collar 25 is moved toattach it preferably at the level of the center of gravity of the unitso composed. The same operation as before is performed to assemble theload 88 with the previous unit, then the platform 10 is brought backinto the storage area and the unit 84 is lowered after having previouslylowered the guides 14, centering by the spigots 22 on the guides 11 inorder to guide the unit as far as the end of the lower part of thepassage at the bottom of the well. The retaining collar 25 can then beraised again as indicated in FIG. 15 and the opening panels 31, 32 canbe closed again and employed with any sort of clamping device 91 forconnecting pipes 90 to the unit that is being lowered to the seabed.

This method thus enables very heavy loads to be lowered and cumbersomeloads to be transported after as sembly in the well, which could neitherbe assembled in a storage area on the main deck of a ship of averagetonnage nor easily erected underwater.

What is claimed is:

1. A method of unloading an underwater apparatus from an installation onthe water surface subjected to the action of ground swell and waves andcomprising a vdeck carrying a derrick, a well straight below the derrickand opening into a storage area below the deck, a platform capable ofsupporting and attaching loads positionable'across the well, and loadtransport means in the storage area, the method comprising: making aload fast with the transport means, transporting the load to theplatform when the platform spans the well, making the load fast with theplatform, disengaging the load from the transport means, moving thetransport means back into the storage area, positioning lateral guidemeans in contact with the load, connecting the load to hoisting means ofthe derrick, disengaging the load from the platform, drawing theplatform back out of the well, and lowering the load down the well whileguiding it laterally.

2. A method as in claim 1, in which a frame is positioned around theload at the level of the center of gravity of the load and which ispositioned by vertical guides during lowering.

3. A method as in claim 2, in which the vertical guides are displacedaway from the load during the application of the frame to the load.

1. A method of unloading an underwater apparatus from an installation onthe water surface subjected to the action of ground swell and waves andcomprising a deck carrying a derrick, a well straight below the derrickand opening into a storage area below the deck, a platform capable ofsupporting and attaching loads positionable across the well, and loadtransport means in the storage area, the method comprising: making aload fast with the transport means, transporting the load to theplatform when the platform spans the well, making the load fast with theplatform, disengaging the load from the transport means, moving thetransport means back into the storage area, positioning lateral guidemeans in contact with the load, connecting the load to hoisting means ofthe derrick, disengaging the load from the platform, drawing theplatform back out of the well, and lowering the load down the well whileguiding it laterally.
 2. A method as in claim 1, in which a frame ispositioned around the load at the level of the center of gravity of theload and which is positioned by vertical guides during lowering.
 3. Amethod as in claim 2, in which the vertical guides are displaced awayfrom the load during the application of the frame to the load.